CryptSetKeyParam info  Overview  Group

The CryptSetKeyParam function lets applications customize various aspects of a key’s operations.

Generally, this function is used to set session-specific parameters on symmetric keys. Note that the base keying material is not accessible by this function.

The Microsoft RSA Base Provider has no settable parameters on key exchange or signature keys. However, custom providers may define parameters that can be set on these keys.

BOOL CRYPTFUNC CryptSetKeyParam(

Parameters

hKey

[in] A handle to the key on which to set parameters.

dwParam

[in] The parameter number. See the “Remarks” section for a list of valid parameters.

pbData

[in] The parameter data buffer. Place the parameter data in this buffer before calling CryptSetKeyParam. The form of this data will vary, depending on the parameter number.

dwFlags

[in] The flag values. This parameter is reserved for future use and should always be zero.

Remarks

For all session key types, the dwParam value can be set to one of the following key parameter types;

If a block cipher session key is specified by hKey, the dwParam value can also be set to one of the following parameter types.

Return Values

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To retrieve extended error information, use the GetLastError function.

The following table lists the error codes most commonly returned by the GetLastError function. The error codes prefaced by “NTE” are generated by the particular CSP you are using.

Example

#include <wincrypt.h>



HCRYPTPROV hProv = 0;

HCRYPTKEY hKey = 0;

DWORD dwMode;

BYTE pbData[16];

DWORD dwCount;

DWORD i;



// Get handle to user default provider.

if(!CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_FULL, 0)) {

    printf("Error %x during CryptAcquireContext!\n", GetLastError());

    goto done;

}



// Create random block cipher session key.

if(!CryptGenKey(hProv, CALG_RC2, CRYPT_EXPORTABLE, &hKey)) {

    printf("Error %x during CryptGenKey!\n", GetLastError());

    goto done;

}



// Set the cipher mode.

dwMode = CRYPT_MODE_ECB;

if(!CryptSetKeyParam(hKey, KP_MODE, &dwMode, 0)) {

    printf("Error %x during CryptSetKeyParam!\n", GetLastError());

    goto done;

}



// Generate random initialization vector.

if(!CryptGenRandom(hProv, 8, pbData)) {

    printf("Error %x during CryptGenRandom!\n", GetLastError());

    goto done;

}



// Set initialization vector.

if(!CryptSetKeyParam(hKey, KP_IV, pbData, 0)) {

    printf("Error %x during CryptGetKeyParam!\n", GetLastError());

    goto done;

}



// Do something with 'hKey'.

...



done:



// Destroy session key.

if(hKey != 0) CryptDestroyKey(hKey);



// Release provider handle.

if(hProv != 0) CryptReleaseContext(hProv, 0);

 

See Also

CryptGenKey, CryptGetKeyParam

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